Propagation and reestablishment of endangered plant species in Oberlausitz (Saxony).
From 2012 to 2015, the reestablishment of 10 plant species in Oberlausitz (Eastern Saxony) was experimentally investigated. The species selected were those of non-intensive agricultural land, with five from damp habitats and five from warm, dry habitats. These plants had either been widespread historically or have a distribution hotspot in Oberlausitz. All ten species are currently highly endangered and mostly threatened by extinction in Saxony. Plants were propagated from seeds sourced from local wild populations. The garden culture, including stratification, sowing and raising young plants, was done ex situ in a farm in Friedersdorf (Markersdorf). Cultures of all species were also established there to ensure species survival and provide future sources of seed. Between 2013 and 2015, c. 3500 young plants were planted at more than 40 sites either used non-intensively by agriculture or recently created by man. Only a small fraction of these plants established. For some species, hardly any plants could be rediscovered the following year. Plants within a single locality showed little variation in their extent of establishment, even though each species was provided with a wide range of environmental conditions. Changes in agricultural land use over the last decades are the main cause of species decline and of setbacks to their recolonisation. Our monitoring of the success of the planting efforts indicates that, amongst other unfavourable factors, the Spanish slug (Arion lusitanicus auct no Mabille) plays a more important role as a pest than previously considered.